Staple guns are well known hand-held tools adapted to drive staples into a workpiece. Arrow Fastener Co. manufactures and sells numerous models of such devices, including the manually operated non-powered staple gun sold under the T 50® brand name, and more recently powered models, such as the cordless CT 50™ staple gun.
It is known to provide a wire guide for a staple gun, as disclosed for example in U.S. Pat. No. 5,884,829, and U.S. patent application Ser. No. 12/920,395, filed Aug. 31, 2010 both of which are assigned to the Arrow Fastener Co. and incorporated herein by reference. A wire guide is an element having a recessed surface that fits around a wire or cable to be stapled to a wall or workpiece to position the staple gun so that a staple can be driven reliably over the wire or cable to attach it to the workpiece. The wire guide itself typically has surfaces on either side of the recess which receives the wire or cable that are positioned against the surface to be stapled during the staple driving operation. These serve to space the staple driving end from the wire to prevent the staple bight from being driven into the wire.
Previously proposed wire guide devices have been somewhat complicated to manufacture and cumbersome to use. For example the guide disclosed in U.S. Patent Publication No. 2007/0039994 uses a rotatable dial having a partially gear toothed peripheral surface that engages a pivotally mounted guide. The dial extends from one side of the staple gun and, when rotated, rotates the guide into or out of the staple gun housing. This requires a somewhat wider front housing than normal and the dial is difficult to operate. In addition, a separate, preferably spring biased retaining structure is required to functionally retain the dial so that the guide is held in its deployed or retracted position.
The staple guide of U.S. patent application Ser. No. 12/920,395, discussed above, is somewhat simpler but also requires multiple components, including a separate spring. That device uses a rotatable knob or switch to rotate a generally oval cam which drives the wire guide into or out of the housing. The knob is located on the front of the housing and has a small protrusion for the operator to use to turn the knob. This is difficult to do, particularly in work gloves.